c# – 为什么多线程在这里表现更差？

现在我想通过将它分成两个线程来加快速度……但是出于一些奇怪的原因,每个线程执行HALF工作量的时间需要64％的时间,我想知道为什么会这样？

这可能是由于某种CPU缓存效应？我该怎么做呢？

我以前用lambda表达式尝试了8个线程,但它总是大约1400毫秒,但是在单线程中我常常得到850毫秒.此外,当我让一个线程完成所有工作时,我花了830毫秒.我只是不明白,有人知道这里的原因吗？

码：

class Program
    {
        static int count = 0x10000000;
        static int half = count / 2;
        static BitArray bitArray = new BitArray(count);

        static unsafe void Main(string[] args)
        {
            Stopwatch sw = Stopwatch.StartNew();

#if SINGLE
            for (int i = 0; i < bitArray.Count; i += 2)
                bitArray.Set(i,true);
#else
            Thread thread1 = new Thread(Thread1);
            Thread thread2 = new Thread(Thread2);
            thread1.Start();
            thread2.Start();
            thread1.Join();
            thread2.Join();
#endif
            sw.Stop();

            Console.WriteLine(sw.ElapsedMilliseconds);
            Console.ReadLine();
        }

        static void Thread1()
        {
            Stopwatch sw = Stopwatch.StartNew();
            for (int i = 0; i < half; i += 2)
                bitArray.Set(i,true);
            sw.Stop();
            Console.WriteLine("Thread1: {0}",sw.ElapsedMilliseconds);
        }

        static void Thread2()
        {
            Stopwatch sw = Stopwatch.StartNew();
            for (int i = half; i < count; i += 2)
                bitArray.Set(i,true);
            sw.Stop();
            Console.WriteLine("Thread2: {0}",sw.ElapsedMilliseconds);
        }
    }